Mark Webber thinks use of the Drag Reduction System (DRS) in qualifying for the Japanese Grand Prix could "catch a few people out" as they try to attack some of Suzuka's fast corners with their rear wing open.

During Friday practice the Red Bulls and other top teams were attempting the daunting 130R corner with the wing wide open in order to glean a little more lap time from the circuit. Sauber's Kamui Kobayashi also tried to take the corner with his DRS open, but lost the rear of his car and did well to avoid a big accident.

Webber said Red Bull was confident all around the lap after the two sessions, but reckons some drivers will be caught out by the DRS.

"It's a challenging circuit; we know there are a couple of tricky corners that can catch us out and we're all pushing to the limit obviously," he said. "We got some good information today; we ran both tyre compounds and completed some long runs, so not a bad day. I don't think KERS will be a problem here, but it's possible that the DRS might catch a few people out."

Webber's Red Bull team-mate Sebastian Vettel added: "It's not comfortable... I think last year we went generally a bit quicker round here, this year we are a bit slower. It's definitely exciting, not as easy as it used to be - 130R - most of the time we lifted today, usually it was always easy flat. It wasn't today, especially with the DRS open."